What Is At The Edge Of The Universe?

[Haz]

On the subject of the expansion of the universe, the universe may not expand forever, eventually it may slow down and reverse, it may compact inwards and create another Big bang.

The Big bang may not have happened just once, it may have happened numerous times throughout the history of the universe.

Fixed

It's a plausable theory, but the fact the rate of expansion is accelerating, seems to suggest that it's not the case.

As the universe expands to infinity, inverse square law predicts that any gravity between matter will be almost if not zero.

Leaving a long and complicated (beond my knowledge) theory of how it will collapse.

Edited August 10, 2007 by Haz

[Barbara Logan-Price]

a giant rabbi cat

[Rich Pearson]

a post-it note

George Lazenby. This is fun. Your turn again

[ilikeriding]

On the subject of the expansion of the universe, the universe doesn't expand forever, eventually it will slow down and reverse, it will compact inwards and create another Big bang.

The Big bang hasn't happened just once, its happened numerous times throughout the history of the universe.

Noone can possibly know any of this

if it did collapse, surley it'd just turn into a really big black hole

Edited August 10, 2007 by afroman

[Barbara Logan-Price]

Noone can possibly know any of this

apart from allah

[ManxTrialSpaz]

Noone can possibly know any of this

if it did collapse, surley it'd just turn into a really big black hole

But then the pressure of the nothingness around it may proceed to rip it apart as soon as all the matter in the universe is compressed?

[Boswell]

I have a few:

Is there colours that we human cannot see?

If the universe was explained to us would our human minds even be able to understand it?

Whats the point in trying, there is a good chance that the human race will be gone before we even begin to understand the universes secrets.

Also i would like to add that i watched a program on this very topic and it said that pictures taken of the edge of the universe show it's very beggining.

[ManxTrialSpaz]

I have a few:

Is there colours that we human cannot see?

Not in the way you're thinking. Other animals can see Infrared as a colour, but that's all they can see, varying dgrees of heat. In the smae fashion, the only toher things we could see would be differetn rays and waves. Radio waves --> Gamma rays. As to the colours these would be, you can only guess. Its like wondering what a blind person sees in there head? Do they have the full range of colours in their head? Or do they not picture things like we do? Where we picture something in our heads, we see what its physical appearance is. Do blind people just picture an emotion or words that are connected with the object?

But anyways, a bit of a pointless rant, but short answer is no.

[ilikeriding]

But then the pressure of the nothingness around it may proceed to rip it apart as soon as all the matter in the universe is compressed?

well if that happens with your ordinary black holes, then fair enough

Edited August 10, 2007 by afroman

[Dani.]

Roast chicken.

Sorry, I've learned that photons don't have a mass: it makes sense plus the oxford dictionary says it has no mass so I must be right .

Allah would know yeah, it's true.

edit: What? Some Galaxies have been proven to be travelling at several times the speed of light? How the f**k did they do that then?

And yeah, laser light is differnent from normal light, it's monochromatic and coherent for a start not to mention being easily directable and precise, can't imagine the nobel prize winners of '97 shine a light bulb at a cloud of rubidium particles all day. I know there are different weays of cooling atoms but I was referring to creating a optical molasses not by creating a bose-einstein condensate with a magnetic trap.

Oh yeah, I'm not a science geek don't worry I just had to give a huge presentation (1year of prep) about laser cooling and there rarely comes a chance when you can actually fry people at a subject usually only spoken of by nobel prize winners and nerds.

Edited August 10, 2007 by Dani.

[Danny]

What would happen if you went to the edge of the universe?

You'd see the wombles.

[Tomm]

Also i would like to add that i watched a program on this very topic and it said that pictures taken of the edge of the universe show it's very beggining.

Because the universe is moving at a speed kinda close to the speed of light. So as you look 'back' from the edge, you are seeing the light that was created when the universe was created.

edit: What? Some Galaxies have been proven to be travelling at several times the speed of light?*

*Relative to us. They're not moving at the speed of light themselves - they're just coming towards us as we move towards them. At least I think that's what he's saying?

[Charlie Jennings]

I believe there is a apple store at the edge of the universe. Containing iUFO's. Rip. Burn. Fly.

[Fixed Pants™]

Like erm, can nothing go faster than the speed of light (and have the speed measured) because it would be going too fast to even see it or something?

[Gavyn.]

we can't see anything thats faster than the speed of light but that doesn't mean its not there or that we couldn't measure it.

[Shaun H]

Since when?

If you know something that the rest of the physics world doesn't please do tell!

E=MC^2 holds no matter what right?

A beam of light has energy.

Energy has mass.

Therefore a beam of light has mass.

A photon is part of a beam of light.

Therefore a photon has, although unmeasurable by human means, mass.

I've read a couple of things and I'm no longer sure on this so if someone can explain to me why this is wrong I'd appreciate the education!

Proton has a really small mass indeed. Photon does not.

That's why light has always been considered a wave, and only in more recent years has the theory of wave-particle duality been coined to describe them.

See above.

Fixed

It's a plausable theory, but the fact the rate of expansion is accelerating, seems to suggest that it's not the case.

As the universe expands to infinity, inverse square law predicts that any gravity between matter will be almost if not zero.

Leaving a long and complicated (beond my knowledge) theory of how it will collapse.

But the rate of acceleration of rate of expansion is slowing. There are 3 theories related to the expansion/shrinking of the universe.

1. The mass density in the Universe is low enough that the expansion will continue indefinitely.

2. The mass density in the Universe is at just the right level to cause the expansion to slow and stop indefinitely (our Universe is uncannily close to this, however "dark matter" isn't accounted for in most measurements)

3. The mass density in the Universe is high enough that the expansion will slow and stop and then the Universe will begin to collapse back in on itself (The Big Crunch). Possibly resulting in another Big Bang and another Universe starting all over again.

[Haz]

E=MC^2 holds no matter what right?

A beam of light has energy.

Energy has mass.

Therefore a beam of light has mass.

A photon is part of a beam of light.

Therefore a photon has, although unmeasurable by human means, mass.

I've read a couple of things and I'm no longer sure on this so if someone can explain to me why this is wrong I'd appreciate the education!

It's just a massless particle. It's not the same as an electron where at GCSE you are told they are massless or whatever, these are considered massless to pretty must every physicist.

On the whole, it's jsut accepted.

But the rate of acceleration of rate of expansion is slowing. There are 3 theories related to the expansion/shrinking of the universe.

1. The mass density in the Universe is low enough that the expansion will continue indefinitely.

2. The mass density in the Universe is at just the right level to cause the expansion to slow and stop indefinitely (our Universe is uncannily close to this, however "dark matter" isn't accounted for in most measurements)

3. The mass density in the Universe is high enough that the expansion will slow and stop and then the Universe will begin to collapse back in on itself (The Big Crunch). Possibly resulting in another Big Bang and another Universe starting all over again.

All true, except that if the rate of expansion were slowing, it would be decelerating.

Our universe is meerly going through a slow point of it's acceleration, it will, some say, begin to speed up again, as our universe is currently modeled by most as an accelerating system.

That's the reason you were probably taught that Hubble's Constant has got closer and closer to what they think is the final value, becasue Hubbles Constant works idealy for a universe expanding at a constant rate, as the universe's expansion slows, the constant will eventually come back into line with the correct Constant for our universes age, before possibly begining toa ccelerate again.

If the universe begins to accelerate, the constant will be too high for our projected age, if it continues to decelerate, the Hubble Constant will begin to look more like that of the model for a universe expanding at a constant speed.

It's kind of hard to explain, but theoretically, those are all posibilities, and we can't be certain if any are correct.

[Tomm]

E=MC^2 holds no matter what right?

A beam of light has energy.

Energy has mass.

Therefore a beam of light has mass.

Er, no. A photon has energy because it has no mass - the mass is converted into energy, at least that's the theory.

That's the reason you were probably taught that Hubble's Constant has got closer and closer to what they think is the final value, becasue Hubbles Constant works idealy for a universe expanding at a constant rate, as the universe's expansion slows, the constant will eventually come back into line with the correct Constant for our universes age, before possibly begining toa ccelerate again.

Weird that the Hubble thing is calculated from stars which are millions of light years away. If the Universe had stopped expanding and was coming crashing back in on itself, we wouldn't see the effects for millions of years.

[Haz]

That's true, but we know to some extent, that the rate of expansion of the universe at that point was accelerating, we could even say that we have reached that point, and the point which was here here, is further again, so that point is relevent to us, but is no longer relevent to the edge, which as you say could be contracting invardly upon itself, but we wouldn't know because of the delay.

How close we really are to that point, I couldn't say. I don't even know if that's a reasonable explanation, but at least in my mind, the idea works?